In order to take these photos you will need:
A camera that will allow you to control the shutter speed, flash
Set your kid up with the lights lit up around them. I only used one strand of lights, but you could use multiple if you want to. Prepare yourself with lots of candy and bribes. One of the keys to these photographs are low light and a slow shutter speed so if your subject moves a lot it will cause blurry photos.
Next turn off your flash. You don't want your flash to add the light you are trying to avoid. Below is a photo done with the flash so you can see how while it makes the image brighter it takes away that Christmas look you are going for.
The 1/6 shot was pretty much just what I was personally looking for, but you can go lower if you so desire.
Other tips for lightening up the photo:
Put your kids in light colored clothes, notice how much the white dress stands out.
Shoot the pictures against a light back drop. I had a particular vision in mind when I shot against the black but that vision aside if I was doing this again I would shoot against white.
Have fun making your pictures "Glow"!